how to get data from text file and plot line graph?

[junlo]

i need to get data from file "data.txt" and then plot two graph.one graph using the first column value from "data.txt" with third column value after 174=XXX, another graph using second column value with third column value after 174=XXX. Since my data is very big, so i hv two text box to let user select what data needed to plot in graph.

For example: if value textbox1=3.8566300, textbox2=100.81888000

i need to get data from (3.8566300 -0.0001) to (3.8566300+0.0001) from the file "data.txt" and plot the first graph.

Second graph is get the data from (100.81888-0.0001) to (100.81888+0.0001) and then plot the line graph.